The aims of this study are (1) to develop and validate an ambulatory monitor to perform continuous monitoring of colon motility from 3 sites for 24-hour periods, (2) to compare patients with constipation-predominant irritable bowel syndrome to normal controls, and (3) to evaluate the efficacy of cisapride 20 mg Q.I.D. for symptoms of constipation-predominant IBS in a double-blind study.